Audio companies which started from DIY users?

I bet there would be many companies once started from DIY users and have grown into well known established companies. Any example you know of?
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VH Audio. Prob not that well known. But Chris used to publish recipes for DIY power cords and interconnects. Now he sells his own brand and other accessories.
Burson Audio of Australia. They started out building for themselves and friends and things took off.
ARC started that way. So did we, back in the late 1970s.
Continuum in Australia also started like this.
Me in 1973. Yikes!